Abstract : The object of this project was to determine the feasibility of employing conventional smoke aerosols as potential countermeasures against laser radiation devices. A pulsed ruby laser, generating radiation at a wave-length of 6943A, was the radiation source. The percent attenuation of the laser beam was measured as the beam traversed hexachloroethane (HC), sulfur trioxide-chlorosulfonic acid (FS), white phosphorus (WP), and fog oil smokes contained in a closed chamber. The percent transmittance of a white-light beam through the smoke was also measured. From these measurements, the relative total obscuring power was calculated for both white-light and laser radiation. It is concluded that : WP, FS, HC, and fog oil smokes attenuate a 0.3-j laser radiation of 6943A by approximately the same percentage as white light. For a 2,000-w laser light power level, the laser white-light transmittance curves for smoke clouds follow the Beer-Lambert relationship down to the 90% attenuation level. Smokescreens appear to be an effective countermeasure against the tested ruby laser. (Author)